ASHRAE Journal - May 2020 - 26

ROUNDTABLE

FIGURE 1 FEI provides an incentive for manufacturers to make fans that are efficient over a wide range of cfm and static pressure.

Peak Efficiency

FEI 0.90
FEI 0.95

FEI 0.80

FEI 1.10
FEI 1.20

FEI 0.70

FEI 0.95
FEI 0.80

Airflow

and exterior lighting wattage section was updated to
better relate to modern lighting equipment and installation methodologies, and to address new lighting systems
such as power over ethernet (PoE) lighting.
* The lighting control requirements for parking garages were updated to account for the usage of LED. This
was done by increasing the stringency of the automatic
power reduction requirement from 30% to 50%, reducing the control time-out from 20 minutes to 10 minutes,
and requiring daylight continuous dimming for parking
garage luminaires within 20 ft (6 m) of wall opening.
New exemptions to the daylight dimming requirements
were added for permanent screens and architectural
elements.
* The daylight dimming requirements for all spaces
were updated to continuous daylight dimming; step
dimming (control points) was eliminated. A new definition for continuous dimming based on NEMA LSD-642014 was added.
Jeff Boldt: We added a new requirement to allow the
option of using ANSI/ASHRAE Standard 90.4-2019,
Energy Standard for Data Centers, instead of Standard 90.1
in computer rooms that have an IT equipment load
larger than 10 kW. It took some time to work out appropriate wording. Essentially big data centers follow 90.4
and smaller computer rooms follow 90.1. Standard 90.4
has more electrical efficiency requirements than 90.1,
and these are very important in large data centers.
We replaced Fan Efficiency Grade (FEG) efficiency
metric with Fan Energy Index (FEI). This has significant
energy savings. FEG mainly required good fan peak
efficiency but wasn't as focused on making good fan

selections as FEI. FEI mainly requires good fan selections, which is where I see the most energy waste in
selecting fans. Basically, kW input must be below a calculated value at the scheduled operating point. So, the
fan must be reasonably efficient also. Manufacturers
selection software should tell you "Compliant with FEI"
or not or just not list non-compliant products. FEI also
provides an incentive for manufacturers to make fans
that are efficient over a wide range of cfm and static
pressure to minimize the number of models needed to
fulfill demand (Figure 1).
FEI will impact first cost in some cases where larger
fan diameters are required to comply, but the energy
savings easily pay off the added first cost. There are
exceptions for embedded fans, safety fans, ceiling fans,
and fans outside of the scope of AMCA 208. There is no
longer an exception for power roof ventilators (PRVs).
The power threshold was lowered from 5 hp to 1 hp. Both
items have significant energy savings. FEI is also a true
wire-to-air method that accounts for factors such as belt
losses.
Many equipment efficiency tables were updated in
90.1-2019. Many of these mimic DOE requirements, but
others are Standard 90.1 requirements. Pump Energy
Index (PEI) was also added to 90.1.
Ceiling fan energy efficiency requirements were
added. These require reporting fan power for large
diameter (≥84.5 in. [2.1 m]) ceiling fans per DOE 10 CFR
430 Appendix U or AMCA 230. Manufacturers must also
report blade tip diameter, rated airflow, and power at
maximum speed. Smaller ceiling fans are covered in the
Energy Star program.

ASHRAE JOURNAL

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M AY 2020

IMAGES COURTESY OF AMCA

Maximum Speed at
Which FEI ≥ 0.95 at
Best Efficiency Point

Pressure

Peak Efficiency

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ASHRAE Journal - May 2020

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